Field of the Invention
This invention relates to a process for the isolation of levulinic acid from an organic solution, to the use of an alkaline aqueous stream in the isolation of levulinic acid, and to a process for the production of levulinic acid from a lignocellulosic biomass.
Description of Related Art
Levulinic acid is a starting molecule for the synthesis of esters known as fuel additive and is known to be useful as plasticiser and solvent. Levulinic acid can be used to synthesize methyl tetrahydrofuran (MTHF) or can be used as a solvent. Other applications of levulinic acid are for example the synthesis of delta-amino levulinic acid used as herbicides and pesticides, diphenolic acid used to synthesize polycarbonates and succinic acid used to make polyesters. Levulinic acid can also be used to produce gamma valerolactone (5-methylbutyrolactone), which in turn can be used for production of adipic acid (1,6-hexanedioic acid).
Levulinic acid may be produced by acid hydrolysis of biomass, as is described for example in U.S. Pat. Nos. 5,608,105, 4,897,497, and 6,054,611. After the acid hydrolysis reaction the levulinic acid must be purified from unwanted components and side products. US2010312006 suggests using solvent-extraction to isolate levulinic acid from a biomass hydrolysate, and suggests including a distillation step after solvent extraction to further purify the separated levulinic acid.